Some thorns using AEILocalInterp incorrectly name the table of operation codes (plain interpolation, derivative, etc.) "opcodes" instead of the correct "operation_codes". Apparently an old api proposals (2.2) did indeed use "opcodes" and the affected thorns are probably descendants of a code using this early API.
The affected thorns are:
- Outflow (probably the one disseminating the incorrect usage, and having picked it up from earlier codes at PSU and GT) maintained by @Roland Haas
- particle_tracerET maintained by @Zach Etienne
- plus a number of non-public Zelmani thorns (since they descend from Outflow)
None of the thorns actually produces incorrect results since they all set the operation to be 0 (plain interpolation) which is the default.
In all cases the fix is to change "opcodes" to "operation_codes" in the name of the table entry. Changing the name of the variables used to hold the operation codes is optional.
Kindly pointed out by @Shawn R who ran into this when actually having to compute derivatives.